package main

import (
	"context"
	"fmt"
	"testing"
	"time"

	messages "git.tornberg.me/go-cart-actor/proto"
	"google.golang.org/grpc"
)

// TestMultiNodeOwnershipNegotiation spins up two gRPC servers (nodeA, nodeB),
// manually links their SyncedPools (bypassing AddRemote's fixed port assumption),
// and verifies that only one node becomes the owner of a new cart while the
// other can still apply a mutation via the remote proxy path.
//
// NOTE:
//   - We manually inject RemoteHostGRPC entries because AddRemote() hard-codes
//     port 1337; to run two distinct servers concurrently we need distinct ports.
//   - This test asserts single ownership consistency rather than the complete
//     quorum semantics (which depend on real discovery + AddRemote).
func TestMultiNodeOwnershipNegotiation(t *testing.T) {
	// Allocate distinct ports for the two nodes.
	const (
		addrA = "127.0.0.1:18081"
		addrB = "127.0.0.1:18082"
		hostA = "nodeA"
		hostB = "nodeB"
	)

	// Create local grain pools.
	poolA := NewGrainLocalPool(1024, time.Minute, spawn)
	poolB := NewGrainLocalPool(1024, time.Minute, spawn)

	// Create synced pools (no discovery).
	syncedA, err := NewSyncedPool(poolA, hostA, nil)
	if err != nil {
		t.Fatalf("nodeA NewSyncedPool error: %v", err)
	}
	syncedB, err := NewSyncedPool(poolB, hostB, nil)
	if err != nil {
		t.Fatalf("nodeB NewSyncedPool error: %v", err)
	}

	// Start gRPC servers (CartActor + ControlPlane) on different ports.
	grpcSrvA, err := StartGRPCServer(addrA, poolA, syncedA)
	if err != nil {
		t.Fatalf("StartGRPCServer A error: %v", err)
	}
	defer grpcSrvA.GracefulStop()

	grpcSrvB, err := StartGRPCServer(addrB, poolB, syncedB)
	if err != nil {
		t.Fatalf("StartGRPCServer B error: %v", err)
	}
	defer grpcSrvB.GracefulStop()

	// Helper to connect one pool to the other's server (manual AddRemote equivalent).
	link := func(src *SyncedPool, remoteHost, remoteAddr string) {
		ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
		defer cancel()
		conn, dialErr := grpc.DialContext(ctx, remoteAddr, grpc.WithInsecure(), grpc.WithBlock())
		if dialErr != nil {
			t.Fatalf("dial %s (%s) failed: %v", remoteHost, remoteAddr, dialErr)
		}
		cartClient := messages.NewCartActorClient(conn)
		controlClient := messages.NewControlPlaneClient(conn)

		src.mu.Lock()
		src.remoteHosts[remoteHost] = &RemoteHostGRPC{
			Host:          remoteHost,
			Conn:          conn,
			CartClient:    cartClient,
			ControlClient: controlClient,
		}
		src.mu.Unlock()
	}

	// Cross-link the two pools.
	link(syncedA, hostB, addrB)
	link(syncedB, hostA, addrA)

	// Allow brief stabilization (control plane pings / no real negotiation needed here).
	time.Sleep(200 * time.Millisecond)

	// Create a deterministic cart id for test readability.
	cartID := ToCartId(fmt.Sprintf("cart-%d", time.Now().UnixNano()))

	// Mutation payload (local ownership claim expected on nodeA).
	addItem := &messages.AddItem{
		ItemId:   1,
		Quantity: 1,
		Price:    1500,
		OrgPrice: 1500,
		Sku:      "sku-test-multi",
		Name:     "Multi Node Test",
		Image:    "/test.png",
		Stock:    2,
		Tax:      2500,
		Country:  "se",
	}

	// Apply mutation on nodeA (should create local grain + claim ownership).
	if _, err := syncedA.Apply(cartID, addItem); err != nil {
		t.Fatalf("nodeA Apply addItem error: %v", err)
	}

	// Validate nodeA local pool has the grain.
	if _, ok := poolA.grains[cartID]; !ok {
		t.Fatalf("nodeA expected local grain ownership but grain missing")
	}

	// Attempt to mutate same cart from nodeB (should route remotely, not create local duplication).
	change := &messages.ChangeQuantity{
		Id:       1, // line id is 1 after first AddItem
		Quantity: 2,
	}

	// Apply on nodeB; if ownership logic works, this will call remote RPC and succeed without creating a local grain.
	if _, err := syncedB.Apply(cartID, change); err != nil {
		t.Fatalf("nodeB remote Apply changeQuantity error: %v", err)
	}

	// NodeB should NOT have a local grain (ownership), but may or may not have a remote proxy
	// entry in remoteIndex depending on internal propagation. We assert it does NOT hold local.
	if _, local := poolB.grains[cartID]; local {
		t.Fatalf("nodeB unexpectedly created local grain (ownership duplication)")
	}

	// Fetch state from nodeB to ensure we see updated quantity (2).
	grainStateB, err := syncedB.Get(cartID)
	if err != nil {
		t.Fatalf("nodeB Get error: %v", err)
	}
	if len(grainStateB.Items) != 1 || grainStateB.Items[0].Quantity != 2 {
		t.Fatalf("nodeB observed inconsistent state: items=%d qty=%d (expected 1 / 2)",
			len(grainStateB.Items),
			func() int {
				if len(grainStateB.Items) == 0 {
					return -1
				}
				return grainStateB.Items[0].Quantity
			}(),
		)
	}

	// Cross-check from nodeA (authoritative) to ensure state matches.
	grainStateA, err := syncedA.Get(cartID)
	if err != nil {
		t.Fatalf("nodeA Get error: %v", err)
	}
	if grainStateA.Items[0].Quantity != 2 {
		t.Fatalf("nodeA authoritative state mismatch: expected qty=2 got %d", grainStateA.Items[0].Quantity)
	}
}